The first 100,000 or so doses of the Pfizer COVID-19 vaccine arrived in Georgia in December and were deployed to hospitals and long-term care facilities around the state. Now that more doses are arriving, how many people will get the vaccine?
One local physician indicated to me that even within the health care community in Glynn County, there is some skepticism over the safety of a vaccine that is being released so quickly. Not all health care workers who are eligible to receive the vaccine are ready to do so. Likewise, in a recent McKinsey and Company consumer survey of 2,466 respondents, more than half the respondents in the United States report they are likely to delay or decline vaccination despite regulatory approval, with safety concerns being the main driver of vaccine hesitancy.
The skepticism, as I understand it, largely revolves around the time that it took for the vaccine to be tested and then released. For a typical vaccine, according to Pfizer’s website, Phase 1 of a clinical trial includes about 100 participants and takes 1 week to several months to complete. Phase 2 includes several hundred participants and takes up to 2 years, Phase 3 can include up to a few thousand participants and takes 1 to 4 years. And the final Phase 4 includes several thousand participants and takes over a year to conclude. In total, at best a typical trial period would take about 3 years. The Pfizer COVID-19 vaccine trial took under a year but did include a similarly large participant pool of 42,000 people.
The big public health and public perception question is, “were corners cut in this modified timeline?” When reviewing the Food and Drug Administration panel’s comments on the Pfizer and Moderna vaccines, I saw a lot of discussion about cost benefit and risk analysis. According to a National Public Radio report, one committee member, Dr. Paul Offit director of the Vaccine Education Center at Children’s Hospital of Philadelphia, framed it this way: “The question that’s being asked [of] us is do we have enough evidence in hand to say that the benefits of this vaccine outweigh what, at the moment as far as severe safety issues, are theoretical risks. I think the answer to that question is clearly yes…The question is never when do you know everything, it’s when do you know enough.”
This kind of risk assessment and reasoning sounded very familiar. My field of study is environmental policy, and in this field risk assessment is an important part of the regulatory and law-making process. Human activities almost always carry an environmental or human health risk. Developing policy around human activities, therefore, requires risk assessment. The challenge is to determine what constitutes “acceptable risk.” Carcinogens, for instance, are generally regarded as having no acceptable threshold of exposure, and yet even The Food Quality Protection Act (FQPA) of 1996 simply requires “reasonable certainty that no harm will result from aggregate exposure,” not zero tolerance. The reason for this is twofold: uncertainty is inherent in modeling future events, and “sufficient information will rarely be available to permit an accurate assessment of environmental health risks…uncertainties arise at all stages of risk assessment” (James E. Anderson, 1984).
These same ideas surround the vaccines. When the vaccines were released in the UK, there were some adverse immuno-responses that were not observed in the trials. Why then did UK health officials release the vaccine? Because uncertainty is inevitable in risk assessment, and they (along with the FDA) found the potential risks are outweighed by the benefits — namely high efficacy rate, increased population immunity and decreased death rates.
Finally, it’s worth mentioning that two terms — efficacy and effectiveness — are often used interchangeably to talk about the vaccine performance, but they have different meaning. Efficacy is the percent reduction of the disease in the optimal clinical conditions. Effectiveness is how the vaccine operates “in the real world” (different primary care settings, broader population) after it is released to the consumer population. In one’s own assessment of risk, these are important to understand.
Whether you feel comfortable taking this early vaccine or not is ultimately a personal choice. While public health policy is based as much on politics as it is on science, we have not yet heard anything on a federal level that indicates that our country will have compulsory participation. Instead, it will be up to us as individuals within the community to read the science, review the assessments, and determine if we are ready to take on the inherent risk in order to reap the anticipated benefits.